DIY Miniature Multimeter Makes It Easy to Measure on Breadboards

A multimeter is an essential tool every engineer and maker should have on hand for testing circuits, voltages, currents, resistance, anything that requires power. Projects often begin with a breadboard, which is another invaluable tool to have on hand when designing circuits. Still, users may often find it difficult to utilize a multimeter to test those circuits at the breadboard level, as some probes have difficulty accessing the socket connections. Multimeters are also not known for being compact devices that can easily fit in a pocket.

"Breadboarding is often the start of great projects but measuring on Breadboards is often not so great," states element 14 contributor Clemens Mayer in his project blog. "The standard multimeter leads don't fit into breadboard holes, and alligator clips are needed to connect to the circuit. There must be a better way! Clem designs a tiny Multimeter dedicated to being used with a breadboard! Easy to connect, battery-powered, and it even has a Wi-Fi so you can view the readings on your phone!"

To help overcome some of those hurdles, element14 contributor Mayer designed a DIY miniature multimeter, which grants easy access for breadboard use, and features a handy OLED display to track values and a USB Type-C port for connectivity options. It packs an ESP32-S2-WROOM microcontroller, a TI INA219 SOIC to handle current and voltage measurements, and a Microchip fixed LDO voltage regulator, all housed on a custom PCB. Mayer also added a battery charger and a 370mAh LiPo rechargeable battery to the multimeter for portability.

Those who would like to recreate his build, Mayer has uploaded a BOM with links to the necessary schematic on his project page.